N/A
1. Field of Invention
Although the inverted pivot methodology may be applicable to any requirement for rotational movement around a displaced axis, its development was driven by a requirement to maximize the length of wooden toy railcars while maintaining their ability to successfully navigate most commercially available wooden railroad curved tracks, switches, inclines and bridges.
2. Description of Prior Art
Currently the overall length of wooden toy railcars is limited by the steepness of the traditional industry inclines (hills, overpasses, etc.). Maximum inclines measure 28 to 32 degrees. The transition from flat track to these inclines is very rapid and two axle toy railcars longer than three inches tend to make coupler contact with the track while beginning the incline which ultimately derails the railcar. This same undesirable track contact and derailment also occurs at the toy railcar""s retransition from incline to level track. In the case of inclines associated with the inverted xe2x80x9cUxe2x80x9d or hump shaped overpass track, the length of the railcar additionally becomes a limiting factor because the underside of extended length toy railcars tend to drag at the pinnacle of the incline.
To date the wooden toy train industry has taken three basic approaches to this problem.
1. One is to use oversized wheels and to move them closer to each car end. Use of oversized wheels allows the railcar to enter the incline transition by holding the car body well above the track and, thus, avoiding undesirable contact with the track. However, this application is currently limited to two axle railcars and even these toy railcars do not successfully navigate the xe2x80x9chump shapedxe2x80x9d trace accessory. Maximum car length is about 3.5 inches. The use of oversized wheels is not desirable because their size in proportion to the railcar body greatly degrades the realism of the toy because the overall height of the toy railcar remains fixed, and thus, the railcar body takes on the appearance of little more than a stick with wheels.
2. A second approach is to use wheel track technology similar to that on full scale railcars. Current wooden toy railroad industry wheel trucks, again, use oversize wheels and a xe2x80x9cTxe2x80x9d shaped pivot pin located in the top of the wheel truck. In this application, the stem of the xe2x80x9cTxe2x80x9d is secured into a bearing housing in the railcar underbody along the xe2x80x9cyxe2x80x9d axis and the top of the xe2x80x9cTxe2x80x9d is positioned in the wheel truck along the wheel truck""s xe2x80x9czxe2x80x9d axis. The wheel truck pivots around both the xe2x80x9cyxe2x80x9d and xe2x80x9czxe2x80x9d axis. While this approach allows the use of a more realistic wheel configuration (wheel trucks vs. two axle) and somewhat longer toy railcars (approx.4+ inches); the disproportional, oversized wheels again detract from the railcars realism as in Item 1 above. This second approach is also bound by the same maximum railcar height limitation as above and, thus, is still relegated to using the undesirable xe2x80x9cstick on wheelsxe2x80x9d appearance.
3. An industry third approach is to use a xe2x80x9crockerxe2x80x9d wheel truck assembly. In this approach, the top of the wheel truck has two flat, slightly declining surfaces which, when attached to the railcar with the use of a pivot pin, allows the wheel truck to xe2x80x9crockxe2x80x9d or pivot along the xe2x80x9czxe2x80x9d axis and spin on the xe2x80x9cyxe2x80x9d axis. The top of the wheel truck is permanently attached to the underside of the railcar along the xe2x80x9cyxe2x80x9d axis. However, this third approach also requires to use oversized wheels and, thus, the xe2x80x9cstick on wheelsxe2x80x9d appearance.
The object of this inverted pivot invention is to provide a new wheel truck assembly using geometry that will allow extended length toy wooden railcars (5 to 6 inches) to successfully navigate the wooden toy train industry""s standard inclined track configurations.
Another object of this invention is to provide a new wheel truck assembly which allows for the use of small diameter wheels, which, in turn, allows for more realistic appearing toy railcars.
In accordance with the teachings of this invention, the use of inverted pivot wheel truck assembly allows:
1. more realistic wooden toy railcars;
2. railcars exceeding five inches or more to successfully navigate steep track inclines including the xe2x80x9chumpxe2x80x9d shaped overpass configuration as described above. The invention may be made of any appropriately configured rigid material.